2 * arch/s390/kernel/process.c
5 * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 * Hartmut Penner (hp@de.ibm.com),
8 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
10 * Derived from "arch/i386/kernel/process.c"
11 * Copyright (C) 1995, Linus Torvalds
15 * This file handles the architecture-dependent parts of process handling..
18 #include <linux/config.h>
19 #include <linux/errno.h>
20 #include <linux/sched.h>
21 #include <linux/kernel.h>
23 #include <linux/smp.h>
24 #include <linux/smp_lock.h>
25 #include <linux/stddef.h>
26 #include <linux/unistd.h>
27 #include <linux/ptrace.h>
28 #include <linux/slab.h>
29 #include <linux/vmalloc.h>
30 #include <linux/user.h>
31 #include <linux/a.out.h>
32 #include <linux/interrupt.h>
33 #include <linux/delay.h>
34 #include <linux/reboot.h>
35 #include <linux/init.h>
37 #include <asm/uaccess.h>
38 #include <asm/pgtable.h>
39 #include <asm/system.h>
41 #include <asm/processor.h>
43 #if defined(CONFIG_VIRT_TIMER) || defined (CONFIG_NO_IDLE_HZ)
44 #include <asm/timer.h>
47 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
50 * Return saved PC of a blocked thread. used in kernel/sched.
51 * resume in entry.S does not create a new stack frame, it
52 * just stores the registers %r6-%r15 to the frame given by
53 * schedule. We want to return the address of the caller of
54 * schedule, so we have to walk the backchain one time to
55 * find the frame schedule() store its return address.
57 unsigned long thread_saved_pc(struct task_struct *tsk)
61 bc = *((unsigned long *) tsk->thread.ksp);
62 #ifndef CONFIG_ARCH_S390X
63 return *((unsigned long *) (bc+56));
65 return *((unsigned long *) (bc+112));
70 * The idle loop on a S390...
73 void default_idle(void)
85 #if defined(CONFIG_VIRT_TIMER) || defined (CONFIG_NO_IDLE_HZ)
87 * hook to stop timers that should not tick while CPU is idle
96 * Wait for external, I/O or machine check interrupt and
97 * switch off machine check bit after the wait has ended.
99 wait_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK | PSW_MASK_WAIT |
100 PSW_MASK_IO | PSW_MASK_EXT;
101 #ifndef CONFIG_ARCH_S390X
104 "0: la %0,1f-0b(%0)\n"
108 "1: la %0,2f-1b(%0)\n"
114 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
115 #else /* CONFIG_ARCH_S390X */
125 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
126 #endif /* CONFIG_ARCH_S390X */
136 void show_regs(struct pt_regs *regs)
138 struct task_struct *tsk = current;
140 printk("CPU: %d %s\n", tsk->thread_info->cpu, print_tainted());
141 printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
142 current->comm, current->pid, (void *) tsk,
143 (void *) tsk->thread.ksp);
145 show_registers(regs);
146 /* Show stack backtrace if pt_regs is from kernel mode */
147 if (!(regs->psw.mask & PSW_MASK_PSTATE))
148 show_trace(0,(unsigned long *) regs->gprs[15]);
151 extern void kernel_thread_starter(void);
153 #ifndef CONFIG_ARCH_S390X
156 "kernel_thread_starter:\n"
165 #else /* CONFIG_ARCH_S390X */
168 "kernel_thread_starter:\n"
177 #endif /* CONFIG_ARCH_S390X */
179 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
183 memset(®s, 0, sizeof(regs));
184 regs.psw.mask = PSW_KERNEL_BITS;
185 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
186 regs.gprs[7] = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
187 regs.gprs[8] = __LC_KERNEL_STACK;
188 regs.gprs[9] = (unsigned long) fn;
189 regs.gprs[10] = (unsigned long) arg;
190 regs.gprs[11] = (unsigned long) do_exit;
193 /* Ok, create the new process.. */
194 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
195 0, ®s, 0, NULL, NULL);
199 * Free current thread data structures etc..
201 void exit_thread(void)
205 void flush_thread(void)
208 current->used_math = 0;
209 clear_tsk_thread_flag(current, TIF_USEDFPU);
212 void release_thread(struct task_struct *dead_task)
216 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
217 unsigned long unused,
218 struct task_struct * p, struct pt_regs * regs)
222 unsigned long back_chain;
226 unsigned long scratch[2];
227 unsigned long gprs[10]; /* gprs 6 -15 */
228 unsigned int fprs[4]; /* fpr 4 and 6 */
229 unsigned int empty[4];
230 struct pt_regs childregs;
233 frame = ((struct stack_frame *)
234 (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
235 p->thread.ksp = (unsigned long) frame;
236 p->set_child_tid = p->clear_child_tid = NULL;
237 /* Store access registers to kernel stack of new process. */
238 frame->childregs = *regs;
239 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
240 frame->childregs.gprs[15] = new_stackp;
241 frame->back_chain = frame->eos = 0;
243 /* new return point is ret_from_fork */
244 frame->gprs[8] = (unsigned long) ret_from_fork;
246 /* fake return stack for resume(), don't go back to schedule */
247 frame->gprs[9] = (unsigned long) frame;
249 /* Save access registers to new thread structure. */
250 save_access_regs(&p->thread.acrs[0]);
252 #ifndef CONFIG_ARCH_S390X
254 * save fprs to current->thread.fp_regs to merge them with
255 * the emulated registers and then copy the result to the child.
257 save_fp_regs(¤t->thread.fp_regs);
258 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
259 sizeof(s390_fp_regs));
260 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
261 /* Set a new TLS ? */
262 if (clone_flags & CLONE_SETTLS)
263 p->thread.acrs[0] = regs->gprs[6];
264 #else /* CONFIG_ARCH_S390X */
265 /* Save the fpu registers to new thread structure. */
266 save_fp_regs(&p->thread.fp_regs);
267 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
268 /* Set a new TLS ? */
269 if (clone_flags & CLONE_SETTLS) {
270 if (test_thread_flag(TIF_31BIT)) {
271 p->thread.acrs[0] = (unsigned int) regs->gprs[6];
273 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
274 p->thread.acrs[1] = (unsigned int) regs->gprs[6];
277 #endif /* CONFIG_ARCH_S390X */
278 /* start new process with ar4 pointing to the correct address space */
279 p->thread.mm_segment = get_fs();
280 /* Don't copy debug registers */
281 memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
286 asmlinkage long sys_fork(struct pt_regs regs)
288 return do_fork(SIGCHLD, regs.gprs[15], ®s, 0, NULL, NULL);
291 asmlinkage long sys_clone(struct pt_regs regs)
293 unsigned long clone_flags;
295 int *parent_tidptr, *child_tidptr;
297 clone_flags = regs.gprs[3];
298 newsp = regs.orig_gpr2;
299 parent_tidptr = (int *) regs.gprs[4];
300 child_tidptr = (int *) regs.gprs[5];
302 newsp = regs.gprs[15];
303 return do_fork(clone_flags & ~CLONE_IDLETASK, newsp, ®s, 0,
304 parent_tidptr, child_tidptr);
308 * This is trivial, and on the face of it looks like it
309 * could equally well be done in user mode.
311 * Not so, for quite unobvious reasons - register pressure.
312 * In user mode vfork() cannot have a stack frame, and if
313 * done by calling the "clone()" system call directly, you
314 * do not have enough call-clobbered registers to hold all
315 * the information you need.
317 asmlinkage long sys_vfork(struct pt_regs regs)
319 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
320 regs.gprs[15], ®s, 0, NULL, NULL);
324 * sys_execve() executes a new program.
326 asmlinkage long sys_execve(struct pt_regs regs)
331 filename = getname((char *) regs.orig_gpr2);
332 error = PTR_ERR(filename);
333 if (IS_ERR(filename))
335 error = do_execve(filename, (char **) regs.gprs[3],
336 (char **) regs.gprs[4], ®s);
338 current->ptrace &= ~PT_DTRACE;
339 current->thread.fp_regs.fpc = 0;
340 if (MACHINE_HAS_IEEE)
341 asm volatile("sfpc %0,%0" : : "d" (0));
350 * fill in the FPU structure for a core dump.
352 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
354 #ifndef CONFIG_ARCH_S390X
356 * save fprs to current->thread.fp_regs to merge them with
357 * the emulated registers and then copy the result to the dump.
359 save_fp_regs(¤t->thread.fp_regs);
360 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
361 #else /* CONFIG_ARCH_S390X */
362 save_fp_regs(fpregs);
363 #endif /* CONFIG_ARCH_S390X */
368 * fill in the user structure for a core dump..
370 void dump_thread(struct pt_regs * regs, struct user * dump)
373 /* changed the size calculations - should hopefully work better. lbt */
374 dump->magic = CMAGIC;
375 dump->start_code = 0;
376 dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
377 dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
378 dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
379 dump->u_dsize -= dump->u_tsize;
381 if (dump->start_stack < TASK_SIZE)
382 dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
383 memcpy(&dump->regs, regs, sizeof(s390_regs));
384 dump_fpu (regs, &dump->regs.fp_regs);
385 dump->regs.per_info = current->thread.per_info;
389 * These bracket the sleeping functions..
391 #define first_sched ((unsigned long) scheduling_functions_start_here)
392 #define last_sched ((unsigned long) scheduling_functions_end_here)
394 unsigned long get_wchan(struct task_struct *p)
396 unsigned long r14, r15, bc;
397 unsigned long stack_page;
399 if (!p || p == current || p->state == TASK_RUNNING)
401 stack_page = (unsigned long) p->thread_info;
403 if (!stack_page || r15 < stack_page ||
404 r15 >= THREAD_SIZE - sizeof(unsigned long) + stack_page)
406 bc = (*(unsigned long *) r15) & PSW_ADDR_INSN;
408 if (bc < stack_page ||
409 bc >= THREAD_SIZE - sizeof(unsigned long) + stack_page)
411 #ifndef CONFIG_ARCH_S390X
412 r14 = (*(unsigned long *) (bc+56)) & PSW_ADDR_INSN;
414 r14 = *(unsigned long *) (bc+112);
416 if (r14 < first_sched || r14 >= last_sched)
418 bc = (*(unsigned long *) bc) & PSW_ADDR_INSN;
419 } while (count++ < 16);